Not sure what you mean by 'consequences' for the unprotected classes in this context, but the age discrimination case would only be valid if both the Over-40 candidate and Under-40 candidate were equally qualified, and the Over-40 candidate was rejected solely because they are too close to retirement age.

Note that due to the letter of the EEO law, there is NOT actionable age discrimination if all candidates were over 40, and for example, the 60 year old was rejected in favor of a 41 year old for the same reason as above.

edit: I should also mention IANAL